my 1st pump died on it 3rd fill and could not wait for the pump to be replaced so I got a 80cf tank brand new filled for $200 I paid $49 for the fill adapter and now only use the pump once in a while when I don't want to lug the tank around but thats not very offten!I do not know of anyone who repairs pumps.You should call crosman to see what they say and if that doesn't work try to fix it yourself what do you have to lose! They say the benji pump looks alot like the Hill pupm so take a look at this it might help you out!
http://www.airgunsofarizona.com/BSA/Hill%20Pump%20Rebuild%20Instructions.pdf